Offset Fed Inverted U-shaped Slot Penta-Band Monopole Antenna for UMTS/GSM/WLAN Applications

In this paper, an offset-fed penta-band monopole antenna is presented on a $19.18\times 22.64\times 1.6\text{mm}^{3}$ FR-4 epoxy substrate having a dielectric constant ($\varepsilon_{\mathrm{r}}$) of 4.4. This operates on five resonating frequency bands with good impedance bandwidth. The proposed antenna consists of a radiating element with inverted U-shaped slot and inverted U-shaped partial ground attached with hairline L-shaped slot for generating multiband characteristics. The circuit design equations are used to analyze the inverted U-shaped slot for lower and higher order resonance frequencies. The addition of U-shaped structure with L-shaped slot embedded in partial ground plane provided the mid resonant frequencies with effective gain and improved bandwidth. The proposed antenna is designed for Universal Mobile Telecommunication System (UMTS)/GSM(1.91GHz) and Wireless LAN/Mobile satellite services (MSS)(4.31GHz, 5.61GHz, 6.61GHz and 8.31GHz) applications. The proposed antenna has various advantages like simple and compact design, effective gain and multiband operation.